In today's world, interactive media is a normal part of our everyday lives. It might surprise you, though, to learn that it is a full 40 years since the launch of the world's first ever interactive film. "Kinoautomat", as the system was called, was a hit as Czechoslovakia's entry at the 1967 Expo - before the country's communist authorities effectively killed it off. Now however, four decades later, it has been revived in Prague.
"It is interactive because it's the first film in the world where the audience can change the plot by voting, by pushing buttons. They are choosing several times, nine times throughout the movie. They can choose how the situation will go on.
"Mostly it stops in very dramatic moments, and then an actor comes on stage and asks the audience to decide what the main hero of the movie should do."
The film, a comedy called Man in His House, is repeatedly stopped by an actor who appears on stage in front of the screen at key moments and acts as a kind of master of ceremonies.
At one point for instance for instance he halts the projection just as the film's main protagonist has been flagged down by a traffic policeman while in hot pursuit of his enraged wife in a taxi. Audiences push a green button if they want him to hit the gas, or red if they want him to stop.
The MC uses essentially the same script as the original from 40 years ago, when the Kinoautomat system and this - its only film - caused a sensation at the 1967 World's Fair in Montreal
"The New Yorker magazine at that time wrote that it was really the hit of Expo 67, and Czech people should build a monument to Raduz Cincera, who invented the whole idea. Unfortunately the monument was never built, as in those stupid Communist times it was somehow hidden and forbidden. And now I am trying to build a monument to my daddy."
"That's true. Mr Hornicek was a very popular comic actor in this country. He wasn't able to say a word in English, so he was studying all his role in English - because the film was dubbed into English in London. But the stage which he was acting, or presenting, every day for six months he had studied like a collection of sounds - he didn't understand them at all.
"He was really very surprised when he came the first time in front of an audience in Montreal and started to...produce this collection of sounds, and the audience started to laugh.
"A lot of journalists came to him and wanted to do interviews with Mr Hornicek but he wasn't able to reply. He didn't understand. Then he asked my daddy to teach him one more sentence, which was, I cannot talk with you, but I can drink with you."
Despite the film's success in Montreal, it wasn't shown here in Prague until four years later, in 1971. It was so popular that there were screenings twice a day. But less than a year later the Communists had banned it. Alena Cincerova explains why.
"All this group of authors was so-called 'politically unconfident', they didn't like them so much and I think that was the main reason the film was put in the safe, like many other beautiful films from the so-called New Wave era, the golden era, of Czech cinematography."
Times have changed, of course, and the Kinoautomat has been taken out of the vaults and dusted down. But speaking after a successful first night, Ivo Anderle, manager of the cinema screening the film, says he still feels it is a huge pity the system was not allowed to go further the first time round.
"As you might know, originally at the end of the 60s all the big Hollywood studios were asking Mr Cincera for Kinoautomat licensing. Unfortunately in the Socialist era this was not possible, it was the property of the state which did not care so much about selling it, so Kinoautomat was not lucky."
Now that it has been revived 40 years later, what kind of experience is it for a modern audience? Among those at the premiere was journalist and film maker Erika Hnikova.
"In the beginning I was a little bit interrupted but when the story was going on it started to be more and more interesting, and I really liked it. And in my mind I was also figuring out how the story could go on, if I choose this way or that way. The first half an hour I didn't know but then I really started to like it and I enjoyed it."
Did you feel frustrated when people voted the other way from you?
"(laughs) Yes, a little bit. I was also asking myself, maybe I should come again and to see if there will be opposite changes in the situation."
The film is 40 years old. I'm curious how you think that it has aged.
"Not at all, because it has typical Czech humour which you can see in the films from the '60s. The story works and the main thing for me is to think about if there is...some morality in the film. In your mind you are trying to figure out the situation in your life where you had to choose."
So a novel experience for viewers then. But is the current limited Prague run a last bow? Or could Kinoautomat possibly have some kind of a future? Ivo Anderle again.
"We have a little bit of hope hidden in our hearts that maybe with this revival something will happen. We don't know what, but we were already approached by some people internationally, who are asking us if it's possible to move the system.
"But for us that's the future. We have the three weeks now of the show in Prague, and if it is successful and it proves to be alive and has a lot to say to today's people, we would be more than happy to see if we can travel around the country we will take it around the country, internationally.
"The English version still exists, so things are possible and we will see how far we get."